CEDAR RAPIDS, Iowa, April 13 -- Sen. John McCain (R-Ariz.) campaigned across Iowa on Thursday, sending a clear signal that he is ready to start building a relationship with a state he spurned in his presidential campaign six years ago.

McCain came here to help the state Republican Party and three Republicans running for office, the last stop in a seven-day, six-state tour. He told reporters that he is far from any decision about 2008. He said he is focused on 2006, because "I think it's going to be a tough election" for Republicans.

But the four stops on his schedule here, the team of advisers that accompanied him, and the private meetings he had scheduled along the way all spoke to the seriousness with which he is now preparing for a likely second run for the White House in 2008.

Six years ago, the Arizona senator skipped Iowa's first-in-the-nation caucuses. He chose to make his first stand in New Hampshire, where moderates and independents play a major role in the state's primary, rather than in a Midwestern state whose Republican Party has been dominated by religious and cultural conservatives and where his opposition to ethanol subsidies would have put him on the defensive.

That turned out to be a shrewd decision. Underdog McCain upset then-Gov. George W. Bush of Texas in the New Hampshire primary and turned the nominating process from what had appeared to be a coronation for Bush into a bitter struggle that established McCain, even after losing, into a dominant figure in the GOP.

In Iowa, however, McCain's strategy had created resentment. "I think that Iowans feel that everybody should come here and compete, and I understand that," he said.

Some Republicans say the bad feelings are in the past and that McCain's status as a prisoner of war in Vietnam, Senate power broker and loyalist to President Bush in 2004 has created interest in his candidacy. "I don't think it will make any difference," Ray Hoffman, chairman of the Iowa Republican Party, said when asked whether McCain's decision to skip the state in 2000 is still an obstacle.

Not all agree with that view. And opinions here differ sharply on the question of whether Iowa's most conservative activists will warm to a candidate who has been on the opposite side of so many issues, including immigration and campaign finance reform. Perhaps, more significantly, McCain's criticism of the religious right in 2000 remains a potential obstacle.

Rep. Jim Leach (Iowa), one of the most independent Republicans in the House, said he believes McCain's war record and national stature override specific disagreements with the party's right flank. "There will be no antagonism to John," he said Thursday.

Leach noted that in some past campaigns, conservatives branded certain presidential candidates as unacceptable. "There is no sense of that with John," he said. "He will be nobody's last choice."

But Steve Scheffler, who heads the Iowa Christian Alliance (formerly the Christian Coalition of Iowa), predicted that McCain will never win the hearts or votes of the bulk of religious conservatives. "I don't think he's going to get anywhere," Scheffler said.

McCain has sought to repair a split with the Rev. Jerry Falwell from 2000 and will deliver the commencement address at Falwell's Liberty University in May. But Scheffler said many religious conservatives will be looking at other issues in judging McCain. Scheffler noted that McCain's team had not yet responded to an invitation to appear at a house party with religious conservatives.

Scheffler also pointed to the upcoming Senate vote on a constitutional amendment barring same-sex marriages. He said that if McCain opposes the amendment, as he did before, that would be "political suicide."

Asked about that proposed amendment at a news conference here, McCain said: "I intend to vote against it. I believe in federalism, and I believe each state should decide." Though opposing a national constitutional amendment, McCain is a co-sponsor of a ballot initiative in Arizona that would make same-sex marriages illegal in the state.

McCain found a way to speak positively about ethanol, despite his continued opposition to the subsidies that support it. "At $10 a barrel, I don't think ethanol was a very viable option," he said. "At $60 or $70 a barrel, I think it is to be examined. There's also national security implications."

McCain said the climate-change legislation he has sponsored with Sen. Joseph I. Lieberman (D-Conn.) would create a fund that could be used to invest in ethanol research. But he stated again on Thursday his general opposition to agricultural subsidies. He said he hopes voters here will judge him on his overall record.

McCain campaigned Thursday for Rep. Jim Nussle (R-Iowa), who is running for governor, as well as Jeff Lamberti, a state senator running against Rep. Leonard L. Boswell (D-Iowa). But McCain used the day for his own purposes, as well.

He recently added Iowa native Terry Nelson, who was Bush's political director in 2004, to his national team. On Wednesday, he announced the addition of state Sen. Charles W. Larson Jr., a former state Republican Party chairman, to the team. Both traveled with McCain on Thursday. They have begun the kind of outreach to prominent Republicans here that McCain has been doing in other key early primary and caucus states.

David Roederer, who was Bush's 2004 chairman in Iowa, said McCain runs well in polls here, but he noted that winning support from the true activists remains his challenge. "To win the state, he's going to have to put a lot of time into it," Roederer said.